<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        div{
            width: 100px;
            height: 100px;
        }

        .box1{
            border: 5px solid;
        }

        .box2{
            border: 5px solid;
            border-color: red green blue purple;
        }

        .box3{
            border: 5px solid red;
            border-right: 5px dashed red;
        }

        .box4{
            border: 5px red;
            border-style: solid dashed;
        }

        .box5 {
            border: 5px solid;
            border-bottom:none;
        }

        div.box6{
            height: 0;
            width: 0;
            border:  40px solid transparent;
            border-top: 40px solid #000;
        }
    </style>
</head>
<body>
<div class="box1"></div>
<hr>
<div class="box2"></div>
<hr>
<div class="box3"></div>
<hr>
<div class="box4"></div>
<hr>
<div class="box5"></div>
<hr>
<div class="box6"></div>
<hr>
</body>
</html>